The Screw,machine, cataloged under National Stock Number 5305-00-174-0621, is classified within Federal Supply Class 5305 (Screws) of the Hardware and Abrasives group. Government technical data includes 13 specifications, cited from the U.S. Government catalog. 2 additional reference documents (drawings, advisory and superseded references) are recorded in the U.S. Government catalog. 1 item shares a part number with this NSN in the catalog (possible match — not a government interchangeability claim). Current acquisition status: Active.
| Parameter | Value |
|---|---|
| NSN | 5305-00-174-0621 |
| Item Name | Screw,machine |
| FSC / FSG | 5305 / 53 — Screws |
| Status | ACTIVE |
| Head Height | 0.180 INCHES MINIMUM AND 0.194 INCHES MAXIMUM IN |
| Screw Surface Treatment | ZINC |
| Fastener Length | 0.513 INCHES NOMINAL IN |
| Thread Length | 0.332 INCHES MINIMUM AND 0.372 INCHES MAXIMUM IN |
| Nominal Thread Diameter | 0.250 INCHES IN |
| Head Style | HEXAGON |
| Thread Direction | RIGHT-HAND |
| Width Between Flats | 0.428 INCHES MINIMUM AND 0.438 INCHES MAXIMUM IN |
| Screw Material | STEEL |
| Internal Drive Style | CROSS RECESS TYPE 1 |
| Thread Class | 3A A |
| Thread Quantity Per Inch | 28 |
| Thread Series Designator | UNF |
| Acquisition Status | ACTIVE |
| DEMIL Code | DEMIL A — No Demilitarization Required |
| Hazard | No hazard code in the DLA record (HMIC N) |
| Criticality Code | X |
| Reference | Meaning |
|---|---|
| 180836PC2 | 3/9 Design control — primary reference Navair and Navsea Managed Original Design Activity Dwg Not Material/parts Supplier |
| MILB857CLATYPEB | 4/1 Identification reference U.S. Government activity |
NSN 5305-00-174-0621 is a Screw,machine, classified under FSC 5305, Screws. Status: active.
1 possible match (shared part number, not a government interchangeability claim): 5305-00-208-8341. Verify interchangeability with system specifications before substitution.
Key specifications for 5305-00-174-0621: Head Height: 0.180 INCHES MINIMUM AND 0.194 INCHES MAXIMUM IN; Screw Surface Treatment: ZINC; Fastener Length: 0.513 INCHES NOMINAL IN; Thread Length: 0.332 INCHES MINIMUM AND 0.372 INCHES MAXIMUM IN. 13 specifications are documented in the U.S. Government catalog.
No hazard code in the DLA record (HMIC N). Hazard information on this page is shown exactly as it appears in the DLA record.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-16.
U.S. Government catalog: edition PUBLOGDVD v12.0.0 (OCT 2026), edition date 2026-10-01, retrieved 2026-10-18.